Hypothermia prevention during surgery: comparison between thermal mattress and thermal blanket

This study aimed to compare the efficiency of the thermal blanket and thermal mattress in the prevention of hypothermia during surgery. Thirty-eight randomized patients were divided into two groups (G1 - thermal blanket and G2 - thermal mattress). The variables studied were: length of surgery, length of stay in the post-anesthetic care unit, period without using the device after thermal induction, transport time from the operating room to post-anesthetic care unit, intraoperative fluid infusion, surgery size, anesthetic technique, age, body mass index, esophageal, axillary and operating room temperature. In G2, length of surgery and starch infusion longer was higher (both p=0.03), but no hypothermia occurred. During the surgical anesthetic procedure, the axillary temperature was higher at 120 minutes (p=0.04), and esophageal temperature was higher at 120 (p=0.002) and 180 minutes (p=0.03) and at the end of the procedure (p=0.002). The thermal mattress was more effective in preventing hypothermia during surgery.

Different outcomes of peritoneal catheter percutaneous placement by nephrologists using a trocar versus the Seldinger technique: the experience of two Brazilian centers

A good catheter implantation technique is important to allow effective peritoneal access function and long-term technique survival. Studies regarding results obtained by nephrologists in comparison with different techniques have been limited. The aim of this study was to investigate the rate of early catheter-related complications and catheter survival in two Brazilian centers, according to two different percutaneous methods of catheter implantation performed by nephrologist team. Adult incident patients recruited from January 2006 to July 2013 having undergone first peritoneal dialysis (PD) catheter implantation were included in the analysis. Mechanical and infectious early complication rates were defined as time to the first event occurring up to 3 months. Four hundred and forty-five consecutive Tenckhoff catheters were implanted by nephrologist team percutaneously after antibiotic prophylaxis in an operating room: trocar was used in 349 (78.4 %) and Seldinger technique (ST) in 99 (21.6 %). The ST was significantly associated with a lower rate of leak (16.3 vs 3 %, p = 0.03) and outflow failure due to tip catheter migration (22.6 vs 10.1 %, p = 0.04), while early infectious complication rates were similar between the two groups (p = 0.59). Long-term catheter survival was higher in Seldinger group (log-rank, p = 0.031). By Cox multivariate analysis, adjusted for age, sex, and diabetes, the ST remained independently associated with better catheter survival [HR 0.681 (0.462-0.910), p = 0.04]. As conclusion, our experience showed better PD outcomes with the ST than trocar method of catheter implantation by nephrologist.

Comparando a eficácia da manta térmica com método de aquecimento passivo na prevenção de hipotermia

Hypothermia is a common phenomenon in the perioperative period, and it affects 60 to 90% of patients submitted to anesthetic-surgical procedures. In order to minimize its incidence, warming methods are used. Such methods can be passive, such as orthopedic cotton, sheets and blankets, or active, such as warm-air blankets and thermal mattresses. In this scenario, the present study aimed at comparing two warming methods used in the intraoperative period. Patients submitted to abdominal surgery in the specialties of gynecology and gastric surgery from August to September 2010 were included in the study. After randomization, they were divided into two groups: one using a thermal blanket (group I) and one using orthopedic cotton (group II). At last, 9 patients were included. The variables for each question were considered according to occurrence frequency. Comparison between groups was performed by Student’s t test. With the purpose to analyze whether there was an association, the chi-square test or Fisher’s Exact test was used. Whenever it was applicable for multiple comparisons, Tukey’s test was utilized; p values < 0.05 were considered to be statistically significant for analysis. The sample comprised 6 males and 3 females submitted to gynecological and gastric surgeries. Their mean age was 48 years for group I and 46.2 years for group II. A predominance of general anesthesia was observed. The time of permanence in the operating room ranged from 80 to 360 minutes. With regard to warming parenteral solutions, the procedure was performed on 5 patients, and infusion of warm solution into the abdominal cavity was performed on 50% of the sample. Concerning the warming method used, 5 patients used a thermal blanket. In view of the results presented, it was not possible to conclude which warming method should be used due to sample size

Does occupational exposure to anesthetic gases lead to increase of pro-inflammatory cytokines?

There is great concern about the possible harmful effects of exposure to volatile anesthetics. The current study aimed at evaluating, for the first time, the effects of occupational exposure to anesthetic gases on physicians who work in operating rooms, by determining several inflammatory cytokines. Plasma inflammatory cytokines (IL-1β, -6, -8, -10, -12, TNF-α) were investigated in 30 individuals who were allocated into two groups of 15: the exposed group, consisting of operating room medical personnel exposed to a mixture of anesthetic gases for 3 years, and a control group composed of medical personnel not exposed to anesthetic gases. The concentrations of volatile anesthetics were measured in the operating room by means of an infrared portable analyzer Our findings suggest an increase of the pro-inflammatory IL-8 (p < 0.05) in medical personnel exposed to high concentrations of anesthetic gases, even for a relatively short period.

Transplante multivisceral em suínos: modelo de pesquisa e treinamento

Objective: To present a model for research and training in multivisceral transplantation in pigs. Methods: Eight Large White pigs (four donors and four recipients) were operated. The multivisceral transplant with stomach, duodenum, pancreas, liver and intestine was performed similarly to transplantation in humans with a few differences, described below. Anastomoses were performed as follows: end-to-end from the supra-hepatic vena cava of the graft to the recipient juxta diaphragmatic vena cava; end-to-end from the infra-hepatic vena cava of the graft to the inferior (suprarenal) vena cava of the recipient; and endto-side patch of the aorta of the graft to the infrarenal aorta of the recipient plus digestive reconstruction. Results: The performance of the multivisceral transplantion was possible in all four animals. Reperfusions of the multivisceral graft led to a severe ischemia-reperfusion syndrome, despite flushing of the graft. The animals presented with hypotension and the need for high doses of vasoactive drugs, and all of them were sacrificed after discontinuing these drugs. Conclusion: Some alternatives to minimize the ischemia-reperfusion syndrome, such as the use of another vasoactive drug, use of a third pig merely for blood transfusion, presence of an anesthesia team in the operating room, and reduction of the graft, will be the next steps to enable experimental studies.

Umidificação e aquecimento do gás inalado em estação de anestesia com baixo fluxo de gases frescos com ou sem isolamento térmico do circuito ventilatório e com ou sem permutador de umidade e temperatura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Umidificação e aquecimento do gás inalado em estação de anestesia com baixo fluxo de gases frescos com ou sem isolamento térmico do circuito ventilatório e com ou sem permutador de umidade e temperatura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Association Between Use of Lung-Protective Ventilation With Lower Tidal Volumes and Clinical Outcomes Among Patients Without Acute Respiratory Distress Syndrome A Meta-analysis

Context Lung-protective mechanical ventilation with the use of lower tidal volumes has been found to improve outcomes of patients with acute respiratory distress syndrome (ARDS). It has been suggested that use of lower tidal volumes also benefits patients who do not have ARDS. Objective To determine whether use of lower tidal volumes is associated with improved outcomes of patients receiving ventilation who do not have ARDS. Data Sources MEDLINE, CINAHL, Web of Science, and Cochrane Central Register of Controlled Trials up to August 2012. Study Selection Eligible studies evaluated use of lower vs higher tidal volumes in patients without ARDS at onset of mechanical ventilation and reported lung injury development, overall mortality, pulmonary infection, atelectasis, and biochemical alterations. Data Extraction Three reviewers extracted data on study characteristics, methods, and outcomes. Disagreement was resolved by consensus. Data Synthesis Twenty articles (2822 participants) were included. Meta-analysis using a fixed-effects model showed a decrease in lung injury development (risk ratio [RR], 0.33; 95% CI, 0.23 to 0.47; I-2, 0%; number needed to treat [NNT], 11), and mortality (RR, 0.64; 95% CI, 0.46 to 0.89; I-2, 0%; NNT, 23) in patients receiving ventilation with lower tidal volumes. The results of lung injury development were similar when stratified by the type of study (randomized vs nonrandomized) and were significant only in randomized trials for pulmonary infection and only in nonrandomized trials for mortality. Meta-analysis using a random-effects model showed, in protective ventilation groups, a lower incidence of pulmonary infection (RR, 0.45; 95% CI, 0.22 to 0.92; I-2, 32%; NNT, 26), lower mean (SD) hospital length of stay (6.91 [2.36] vs 8.87 [2.93] days, respectively; standardized mean difference [SMD], 0.51; 95% CI, 0.20 to 0.82; I-2, 75%), higher mean (SD) PaCO2 levels (41.05 [3.79] vs 37.90 [4.19] mm Hg, respectively; SMD, -0.51; 95% CI, -0.70 to -0.32; I-2, 54%), and lower mean (SD) pH values (7.37 [0.03] vs 7.40 [0.04], respectively; SMD, 1.16; 95% CI, 0.31 to 2.02; I-2, 96%) but similar mean (SD) ratios of PaO2 to fraction of inspired oxygen (304.40 [65.7] vs 312.97 [68.13], respectively; SMD, 0.11; 95% CI, -0.06 to 0.27; I-2, 60%). Tidal volume gradients between the 2 groups did not influence significantly the final results. Conclusions Among patients without ARDS, protective ventilation with lower tidal volumes was associated with better clinical outcomes. Some of the limitations of the meta-analysis were the mixed setting of mechanical ventilation (intensive care unit or operating room) and the duration of mechanical ventilation. JAMA. 2012;308(16):1651-1659 www.jama.com

ENSINO DE ENFERMAGEM EM CENTRO CIRÚRGICO: TRANSFORMAÇÕES DA DISCIPLINA NA ESCOLA DE ENFERMAGEM DA USP (BRASIL)

Este artigo tem por objetivos apresentar uma síntese da evolução do conteúdo de bloco cirúrgico na Escola de Enfermagem da Universidade de São Paulo (EEUSP) e uma reflexão sobre as Diretrizes Curriculares Nacionais do Curso de Graduação em Enfermagem (DCN). O estudo se desenvolveu a partir de um breve histórico do desenvolvimento da enfermagem em centro cirúrgico na prática profissional e sua inserção no currículo de graduação da EEUSP. As Diretrizes Curriculares Nacionais têm seu mérito ao assegurar às instituições de ensino superior a liberdade na composição da carga horária a ser cumprida para a integralização dos currículos e na especificação das unidades de estudo a serem ministradas, porém, as competências e habilidades propostas são inespecíficas. Entendemos que o enfermeiro generalista é aquele que tem oportunidades de aprendizado teórico prático para atuar em todos os cenários de cuidado, área e níveis de atenção em saúde.

Ensino de enfermagem em centro cirúrgico: transformações da disciplina na Escola de Enfermagem da USP (Brasil)

Este artigo tem por objetivos apresentar uma síntese da evolução do conteúdo de bloco cirúrgico na Escola de Enfermagem da Universidade de São Paulo (EEUSP) e uma reflexão sobre as Diretrizes Curriculares Nacionais do Curso de Graduação em Enfermagem (DCN). O estudo se desenvolveu a partir de um breve histórico do desenvolvimento da enfermagem em centro cirúrgico na prática profissional e sua inserção no currículo de graduação da EEUSP. As Diretrizes Curriculares Nacionais têm seu mérito ao assegurar às instituições de ensino superior a liberdade na composição da carga horária a ser cumprida para a integralização dos currículos e na especificação das unidades de estudo a serem ministradas, porém, as competências e habilidades propostas são inespecíficas. Entendemos que o enfermeiro generalista é aquele que tem oportunidades de aprendizado teórico prático para atuar em todos os cenários de cuidado, área e níveis de atenção em saúde.

Revisão sistemática sobre antissepsia cirúrgica das mãos com preparação alcoólica em comparação aos produtos tradicionais

A antissepsia cirúrgica das mãos visa à prevenção de infecções do sítio cirúrgico, importante causa de morbimortalidade pós-operatória e aumento dos custos hospitalares. Este estudo teve como objetivo comparar a eficácia de preparações alcoólicas com os produtos tradicionais na antissepsia cirúrgica das mãos por meio de uma revisão sistemática da literatura. Foram considerados estudos primários ou secundários, tendo como desfecho a contagem microbiana das mãos ou taxas de infecções do sítio cirúrgico. A busca foi realizada no Portal BVS, PubMed, Ask e MEDLINE. Foram selecionados 25 estudos (2 revisões sistemáticas, 19 experimentais e 4 de coorte). As preparações alcoólicas tiveram uma redução microbiana igual e/ou maior aos produtos tradicionais em 17 estudos e inferior em 4; as taxas de infecções do sítio cirúrgico foram similares. Portanto, existem evidências científicas que suportam a segurança das preparações alcoólicas para antissepsia cirúrgica das mãos.

Primary stability in cementless total hip replacement: measurement techniques and aided-surgery

Primary stability of stems in cementless total hip replacements is recognized to play a critical role for long-term survival and thus for the success of the overall surgical procedure. In Literature, several studies addressed this important issue. Different approaches have been explored aiming to evaluate the extent of stability achieved during surgery. Some of these are in-vitro protocols while other tools are coinceived for the post-operative assessment of prosthesis migration relative to the host bone. In vitro protocols reported in the literature are not exportable to the operating room. Anyway most of them show a good overall accuracy. The RSA, EBRA and the radiographic analysis are currently used to check the healing process of the implanted femur at different follow-ups, evaluating implant migration, occurance of bone resorption or osteolysis at the interface. These methods are important for follow up and clinical study but do not assist the surgeon during implantation. At the time I started my Ph.D Study in Bioengineering, only one study had been undertaken to measure stability intra-operatively. No follow-up was presented to describe further results obtained with that device. In this scenario, it was believed that an instrument that could measure intra-operatively the stability achieved by an implanted stem would consistently improve the rate of success. This instrument should be accurate and should give to the surgeon during implantation a quick answer concerning the stability of the implanted stem. With this aim, an intra-operative device was designed, developed and validated. The device is meant to help the surgeon to decide how much to press-fit the implant. It is essentially made of a torsional load cell, able to measure the extent of torque applied by the surgeon to test primary stability, an angular sensor that measure the relative angular displacement between stem and femur, a rigid connector that enable connecting the device to the stem, and all the electronics for signals conditioning. The device was successfully validated in-vitro, showing a good overall accuracy in discriminating stable from unstable implants. Repeatability tests showed that the device was reliable. A calibration procedure was then performed in order to convert the angular readout into a linear displacement measurement, which is an information clinically relevant and simple to read in real-time by the surgeon. The second study reported in my thesis, concerns the evaluation of the possibility to have predictive information regarding the primary stability of a cementless stem, by measuring the micromotion of the last rasp used by the surgeon to prepare the femoral canal. This information would be really useful to the surgeon, who could check prior to the implantation process if the planned stem size can achieve a sufficient degree of primary stability, under optimal press fitting conditions. An intra-operative tool was developed to this aim. It was derived from a previously validated device, which was adapted for the specific purpose. The device is able to measure the relative micromotion between the femur and the rasp, when a torsional load is applied. An in-vitro protocol was developed and validated on both composite and cadaveric specimens. High correlation was observed between one of the parameters extracted form the acquisitions made on the rasp and the stability of the corresponding stem, when optimally press-fitted by the surgeon. After tuning in-vitro the protocol as in a closed loop, verification was made on two hip patients, confirming the results obtained in-vitro and highlighting the independence of the rasp indicator from the bone quality, anatomy and preserving conditions of the tested specimens, and from the sharpening of the rasp blades. The third study is related to an approach that have been recently explored in the orthopaedic community, but that was already in use in other scientific fields. It is based on the vibration analysis technique. This method has been successfully used to investigate the mechanical properties of the bone and its application to evaluate the extent of fixation of dental implants has been explored, even if its validity in this field is still under discussion. Several studies have been published recently on the stability assessment of hip implants by vibration analysis. The aim of the reported study was to develop and validate a prototype device based on the vibration analysis technique to measure intra-operatively the extent of implant stability. The expected advantages of a vibration-based device are easier clinical use, smaller dimensions and minor overall cost with respect to other devices based on direct micromotion measurement. The prototype developed consists of a piezoelectric exciter connected to the stem and an accelerometer attached to the femur. Preliminary tests were performed on four composite femurs implanted with a conventional stem. The results showed that the input signal was repeatable and the output could be recorded accurately. The fourth study concerns the application of the device based on the vibration analysis technique to several cases, considering both composite and cadaveric specimens. Different degrees of bone quality were tested, as well as different femur anatomies and several levels of press-fitting were considered. The aim of the study was to verify if it is possible to discriminate between stable and quasi-stable implants, because this is the most challenging detection for the surgeon in the operation room. Moreover, it was possible to validate the measurement protocol by comparing the results of the acquisitions made with the vibration-based tool to two reference measurements made by means of a validated technique, and a validated device. The results highlighted that the most sensitive parameter to stability is the shift in resonance frequency of the stem-bone system, showing high correlation with residual micromotion on all the tested specimens. Thus, it seems possible to discriminate between many levels of stability, from the grossly loosened implant, through the quasi-stable implants, to the definitely stable one. Finally, an additional study was performed on a different type of hip prosthesis, which has recently gained great interest thus becoming fairly popular in some countries in the last few years: the hip resurfacing prosthesis. The study was motivated by the following rationale: although bone-prosthesis micromotion is known to influence the stability of total hip replacement, its effect on the outcome of resurfacing implants has not been investigated in-vitro yet, but only clinically. Thus the work was aimed at verifying if it was possible to apply to the resurfacing prosthesis one of the intraoperative devices just validated for the measurement of the micromotion in the resurfacing implants. To do that, a preliminary study was performed in order to evaluate the extent of migration and the typical elastic movement for an epiphyseal prosthesis. An in-vitro procedure was developed to measure micromotions of resurfacing implants. This included a set of in-vitro loading scenarios that covers the range of directions covered by hip resultant forces in the most typical motor-tasks. The applicability of the protocol was assessed on two different commercial designs and on different head sizes. The repeatability and reproducibility were excellent (comparable to the best previously published protocols for standard cemented hip stems). Results showed that the procedure is accurate enough to detect micromotions of the order of few microns. The protocol proposed was thus completely validated. The results of the study demonstrated that the application of an intra-operative device to the resurfacing implants is not necessary, as the typical micromovement associated to this type of prosthesis could be considered negligible and thus not critical for the stabilization process. Concluding, four intra-operative tools have been developed and fully validated during these three years of research activity. The use in the clinical setting was tested for one of the devices, which could be used right now by the surgeon to evaluate the degree of stability achieved through the press-fitting procedure. The tool adapted to be used on the rasp was a good predictor of the stability of the stem. Thus it could be useful for the surgeon while checking if the pre-operative planning was correct. The device based on the vibration technique showed great accuracy, small dimensions, and thus has a great potential to become an instrument appreciated by the surgeon. It still need a clinical evaluation, and must be industrialized as well. The in-vitro tool worked very well, and can be applied for assessing resurfacing implants pre-clinically.

Toward optimal display of physiologic status in critical care: I. Recreating bedside displays from archived physiologic data

BACKGROUND: Physiologic data display is essential to decision making in critical care. Current displays echo first-generation hemodynamic monitors dating to the 1970s and have not kept pace with new insights into physiology or the needs of clinicians who must make progressively more complex decisions about their patients. The effectiveness of any redesign must be tested before deployment. Tools that compare current displays with novel presentations of processed physiologic data are required. Regenerating conventional physiologic displays from archived physiologic data is an essential first step. OBJECTIVES: The purposes of the study were to (1) describe the SSSI (single sensor single indicator) paradigm that is currently used for physiologic signal displays, (2) identify and discuss possible extensions and enhancements of the SSSI paradigm, and (3) develop a general approach and a software prototype to construct such "extended SSSI displays" from raw data. RESULTS: We present Multi Wave Animator (MWA) framework-a set of open source MATLAB (MathWorks, Inc., Natick, MA, USA) scripts aimed to create dynamic visualizations (eg, video files in AVI format) of patient vital signs recorded from bedside (intensive care unit or operating room) monitors. Multi Wave Animator creates animations in which vital signs are displayed to mimic their appearance on current bedside monitors. The source code of MWA is freely available online together with a detailed tutorial and sample data sets.

Comparison of actual surgical outcomes and 3-dimensional surgical simulations

PURPOSE: The advent of imaging software programs has proved to be useful for diagnosis, treatment planning, and outcome measurement, but precision of 3-dimensional (3D) surgical simulation still needs to be tested. This study was conducted to determine whether the virtual surgery performed on 3D models constructed from cone-beam computed tomography (CBCT) can correctly simulate the actual surgical outcome and to validate the ability of this emerging technology to recreate the orthognathic surgery hard tissue movements in 3 translational and 3 rotational planes of space. MATERIALS AND METHODS: Construction of pre- and postsurgery 3D models from CBCTs of 14 patients who had combined maxillary advancement and mandibular setback surgery and 6 patients who had 1-piece maxillary advancement surgery was performed. The postsurgery and virtually simulated surgery 3D models were registered at the cranial base to quantify differences between simulated and actual surgery models. Hotelling t tests were used to assess the differences between simulated and actual surgical outcomes. RESULTS: For all anatomic regions of interest, there was no statistically significant difference between the simulated and the actual surgical models. The right lateral ramus was the only region that showed a statistically significant, but small difference when comparing 2- and 1-jaw surgeries. CONCLUSIONS: Virtual surgical methods were reliably reproduced. Oral surgery residents could benefit from virtual surgical training. Computer simulation has the potential to increase predictability in the operating room.

Increasing hematocrit above 28% during early resuscitative phase is not associated with decreased mortality following severe traumatic brain injury

To prevent iatrogenic damage, transfusions of red blood cells should be avoided. For this, specific and reliable transfusion triggers must be defined. To date, the optimal hematocrit during the initial operating room (OR) phase is still unclear in patients with severe traumatic brain injury (TBI). We hypothesized that hematocrit values exceeding 28%, the local hematocrit target reached by the end of the initial OR phase, resulted in more complications, increased mortality, and impaired recovery compared to patients in whom hematocrit levels did not exceed 28%.